Comment by mschuster91

> Even IM clients were possible without JS, just plain HTML forms and pure applied skill, which I'll leave as exercise for the reader to figure out.

For the younger generation that didn't get to witness the glorious old days - there were two approaches. The first one is plain old polling which can be done by using "meta refresh" [1], and the second one is chunked responses [2].

IRC was classically done by the latter method, where the server ran essentially one IRC client binary for each requestor.

[1] https://en.wikipedia.org/wiki/Meta_refresh

[2] https://stackoverflow.com/questions/2481858/how-to-make-php-...